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Manual dynamic enhancement with openjpa on intellij

I am trying to use openjpa and mysql to persist a single class, nothing dramatic really.
Attempt to cast instance "xxx" to PersistenceCapable failed. Ensure that it has been enhanced.
So I looked around and found this
https://openjpa.apache.org/builds/2.2.1/apache-openjpa/docs/ref_guide_pc_enhance.html
where they suggest the use of
java -javaagent:/home/dev/openjpa/lib/openjpa.jar com.xyz.Main
Now I added this to my VM-Options in my intellij runtime configurations:
-javaagent:/home/xxx/Downloads/apache-openjpa-3.1.2/openjpa-all-3.1.2.jar main.java.entity.Post
But it does not seem to recognise the class:
You have enabled runtime enhancement, but have not specified the set of persistent classes. OpenJPA must look for metadata for every loaded class, which might increase class load times significantly.
I thought the 2nd argument for javaagent is me specifiying the class but I am wrong.
This is my persistence.xml:
<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.2"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_2.xsd">
<!-- Define persistence unit -->
<persistence-unit name="post">
<class>main.java.entity.Post</class>
<properties>
<property name="openjpa.DynamicEnhancementAgent" value="true"/>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/DSTEST" />
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.user" value="xxx" />
<property name="javax.persistence.jdbc.password" value="xxx" />
</properties>
</persistence-unit>
And this is my entity:
package main.java.entity;
import javax.persistence.Entity;
import javax.persistence.Id;
#Entity (name="post")
public class Post {
#Id
private Integer postid;
private String user;
private Integer datum;
private String inhalt;
public Integer getPostid() {
return postid;
}
public void setPostid(Integer postid) {
this.postid = postid;
}
public String getUser() {
return user;
}
public void setUser(String user) {
this.user = user;
}
public Integer getDatum() {
return datum;
}
public void setDatum(Integer datum) {
this.datum = datum;
}
public String getInhalt() {
return inhalt;
}
public void setInhalt(String inhalt) {
this.inhalt = inhalt;
}
}
I am using Intellij on Ubuntu.

Why is my Entity Manager returning empty ResultLists?

I'm having quite the predicament with my Web Application.
For my school project, we have to migrate from classical JDBC Integration to a JPA Integration. As for myself, I've decided to use Hibernate JPA Framework. I've tried in a main inside a SessionBean, it works there. But whenever I integrate it in a Web Servlet, I noticed it returned empty lists. I've tried displaying the size of the lists with System.out.println().
Anyways, I think the problem might be in my persistence.xml, more specifically the lack of a <jta-data-source>something here</jta-data-source> in it.
Here's my persistence.xml, maybe you could see where I'm having issues :
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="PERSISTENCE" transaction-type="JTA">
<description>Hibernate JPA Configuration Example</description>
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
<class>JavaBeans.Employee</class>
<class>JavaBeans.User</class>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver"/>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/JEEPRJ?serverTimezone=Europe/Paris"/>
<property name="javax.persistence.jdbc.user" value="jee"/>
<property name="javax.persistence.jdbc.password" value="jee"/>
<property name="javax.persistence.jdbc.serverTimezone" value="Europe/Paris"/>
<property name="javax.persistence.jdbc.useSSL" value="false"/>
<property name="hibernate.show_sql" value="true"/>
<property name="hibernate.hbm2ddl.auto" value="update"/>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
<property name="hibernate.transaction.jta.platform" value="org.hibernate.service.jta.platform.internal.SunOneJtaPlatform"/>
</properties>
</persistence-unit>
</persistence>
Here's my Session Bean for Employee :
package SessionBeans;
import JavaBeans.Employee;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import java.util.List;
import javax.persistence.Query;
/**
*
*/
#Stateless
public class EmployeeSB {
#PersistenceContext(name="PERSISTENCE")
EntityManager em;
public List<Employee> getAllEmployees(){
String query = "SELECT e FROM Employee e ";
Query q = em.createQuery(query);
List<Employee> employees = q.getResultList();
if(employees!=null){
System.out.println("it's not null list size : " + q.getResultList().size());
for(Employee emp:employees){
System.out.println("id : " + emp.getId());
}
return employees;
}
System.out.println("it's null");
return employees;
}
And my Employee class :
#Entity
#Table(name = "EMPLOYE")
public class Employee implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
public Integer id;
#Size(max = 255)
#Column(name = "NOM")
public String nom;
#Size(max = 255)
#Column(name = "PRENOM")
public String prenom;
#Size(max = 255)
#Column(name = "TELDOMICILE")
public String telDomicile;
#Size(max = 255)
#Column(name = "TELPORTABLE")
public String telPortable;
#Size(max = 255)
#Column(name = "TELPRO")
public String telPro;
#Size(max = 255)
#Column(name = "ADRESSE")
public String adresse;
#Size(max = 255)
#Column(name = "CODEPOSTAL")
public String codePostal;
#Size(max = 255)
#Column(name = "VILLE")
public String ville;
// #Pattern(regexp="[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*#(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?", message="Invalid email")//if the field contains email address consider using this annotation to enforce field validation
#Size(max = 255)
#Column(name = "EMAIL")
public String email;
public Employee() {
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getNom() {
return nom;
}
public void setNom(String nom) {
this.nom = nom;
}
public String getPrenom() {
return prenom;
}
public void setPrenom(String prenom) {
this.prenom = prenom;
}
public String getTelDomicile() {
return telDomicile;
}
public void setTelDomicile(String telDomicile) {
this.telDomicile = telDomicile;
}
public String getTelPortable() {
return telPortable;
}
public void setTelPortable(String telPortable) {
this.telPortable = telPortable;
}
public String getTelPro() {
return telPro;
}
public void setTelPro(String telPro) {
this.telPro = telPro;
}
public String getAdresse() {
return adresse;
}
public void setAdresse(String adresse) {
this.adresse = adresse;
}
public String getCodePostal() {
return codePostal;
}
public void setCodePostal(String codePostal) {
this.codePostal = codePostal;
}
public String getVille() {
return ville;
}
public void setVille(String ville) {
this.ville = ville;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public Employee(String nom, String prenom, String telDomicile, String telPortable, String telPro, String adresse, String codePostal, String ville, String email) {
this.nom = nom;
this.prenom = prenom;
this.telDomicile = telDomicile;
this.telPortable = telPortable;
this.telPro = telPro;
this.adresse = adresse;
this.codePostal = codePostal;
this.ville = ville;
this.email = email;
}
#Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof Employee)) {
return false;
}
Employee other = (Employee) object;
if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
return false;
}
return true;
}
#Override
public String toString() {
return "JavaBeans.Employee[ id=" + id + " ]";
}
}
(Don't mind the French haha).
Anyways, if somebody sees why the entity manager is returning empty lists, that would help me a lot and make me understand where I made my stupid mistake.
Thanks a lot guys and have a great day,
Fares.

If you copy/paste the same code of the above session bean inside the servlet, be careful about transaction management. Since session beans manage transactions as their default behavior, as you did you have not to manage them in the beans. However servlets don't have such this behavior, and it's your own responsibility to implement them.
Be notice that it would be an anti-pattern to implement database related jobs inside servlets which belongs to the view layer. The better approach is using session beans for such this functionality and just call them inside the view layer.

I managed to find where the issue is. Buckle up for the ride cause it's gonna be a long one.
In my persistence.xml I never got to define a <jta-data-source></jta-data-source> because I didn't understand it's goal and why we needed to use it.
Since then I have developed a large amount of knowledge and wisdom (not really, basically trial-and-error philosophy).
So. Enough talking. Straight to the answer.
As I said previously the <jta-data-source></jta-data-source> wasn't defined in the persistence.xml in lieu of a huge <properties></properties> section.
Netbeans IDE generates a file in the WEB-INF folder of your directory. It's called glassfish-resources.xml. Our persistence.xml is somewhat binded to it. In the resources file, we define all of our JDBC connection properties. We name it in a pool through a JNDI.
Therefore our new `persistence.xml looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="m1se_appv2_war_1.0PU" transaction-type="JTA">
<jta-data-source>java:app/DBJEE</jta-data-source>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties/>
</persistence-unit>
</persistence>
And the (in)famous glassfish-resources.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE resources PUBLIC "-//GlassFish.org//DTD GlassFish Application Server 3.1 Resource Definitions//EN" "http://glassfish.org/dtds/glassfish-resources_1_5.dtd">
<resources>
<jdbc-connection-pool allow-non-component-callers="false" associate-with-thread="false" connection-creation-retry-attempts="0" connection-creation-retry-interval-in-seconds="10" connection-leak-reclaim="false" connection-leak-timeout-in-seconds="0" connection-validation-method="auto-commit" datasource-classname="com.mysql.jdbc.jdbc2.optional.MysqlDataSource" fail-all-connections="false" idle-timeout-in-seconds="300" is-connection-validation-required="false" is-isolation-level-guaranteed="true" lazy-connection-association="false" lazy-connection-enlistment="false" match-connections="false" max-connection-usage-count="0" max-pool-size="32" max-wait-time-in-millis="60000" name="mysql_JEEPRJ_jeePool" non-transactional-connections="false" pool-resize-quantity="2" res-type="javax.sql.DataSource" statement-timeout-in-seconds="-1" steady-pool-size="8" validate-atmost-once-period-in-seconds="0" wrap-jdbc-objects="false">
<property name="serverName" value="localhost"/>
<property name="portNumber" value="3306"/>
<property name="databaseName" value="JEEPRJ"/>
<property name="User" value="jee"/>
<property name="Password" value="***"/>
<property name="URL" value="jdbc:mysql://localhost:3306/JEEPRJ?useSSL=false&serverTimezone=Europe/Paris"/>
<property name="driverClass" value="com.mysql.jdbc.Driver"/>
</jdbc-connection-pool>
<jdbc-resource enabled="true" jndi-name="java:app/DBJEE" object-type="user" pool-name="mysql_JEEPRJ_jeePool"/>
</resources>
BTW If you are using MySQL version above 5.7, absolutely define the useSSL property in URL preferably as false if you don't intend to use it.

How can I insert new row in a table using Hibernate?

I'm trying to understand JPA/Hibernate, I'm able to create new database but I don't understand how insert new row in my
database.
This is the code:
import java.io.Serializable;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
#Entity
public class Person implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
private String adress;
private String phoneNumber;
public void setName(String name) {
this.name = name;
}
public void setAdress(String adress) {
this.adress = adress;
}
public void setPhoneNumber(String phoneNumber) {
this.phoneNumber = phoneNumber;
}
public String getName() {
return name;
}
public String getAdress() {
return adress;
}
public String getPhoneNumber() {
return phoneNumber;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
#Override
public int hashCode() {
int hash = 0;
hash += (id != null ? id.hashCode() : 0);
return hash;
}
#Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof Person)) {
return false;
}
Person other = (Person) object;
if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
return false;
}
return true;
}
#Override
public String toString() {
return "entinty.Person[ id=" + id + " ]";
}
}
The class that create the database is:
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
public class Main {
public static void main(String args[]) {
Person p = new Person();
p.setName("xxx");
p.setAdress("yyy");
p.setPhoneNumber("zzz");
EntityManagerFactory emf = javax.persistence.Persistence.createEntityManagerFactory("testPU");
EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
try {
em.persist(p);
em.getTransaction().commit();
} catch (Exception e) {
e.printStackTrace();
em.getTransaction().rollback();
}
em.close();
emf.close();
}
}
At this point I have a table with one row (with written "xxx-yyy-zzz"). How can I add new row? Creating new Person doesn't work because it creates new table... I only find solution using Session and SessionFactory but I'm not able to use it, because I can't understand how generate a hibernate.cfg.xml (and in general how to create a session object).
Is There a solution using only EntityManager? Or how can I generate/write a hibernate.cfg.xml file? Is there a way to generate automatically it using netbeans?
EDIT: this is my persistence.xml file. Where do I have to put the ? I put it in the *** zone but it doesn't work...
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="testPU" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>test.Person</class>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/stackoverflow?zeroDateTimeBehavior=convertToNull"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.password" value="leonida95."/>
<property name="hibernate.cache.provider_class" value="org.hibernate.cache.NoCacheProvider"/>
<property name="javax.persistence.schema-generation.database.action" value="create"/>
*****
</properties>
</persistence-unit>
</persistence>

Inside your Persistence Unit file you'll have something like
<properties>
<property name="hibernate.connection.url" value="..." />
<property name="hibernate.connection.driver_class" value="..."/>
...
</properties>
To create tables when the EntityManagerFactory is constructed, just add
<property name="hibernate.hbm2ddl.auto" value="create" />
Your code works fine.
You can call persist as many times as you want, and it will add rows to the target table.
em.persist(person1);
em.persist(person2);
...
persist does not create a table.

Problems building up Java project with JPA

I am trying to get a javax.persistence running, but I get erros.
I built up a little project for testing, creating an entity class, the persistence.xml, and the running process:
Entity class:
package glasses;
import java.io.Serializable;
import javax.persistence.Entity;
import javax.persistence.Id;
#Entity
public class Hund implements Serializable {
#Id
private long id;
private String name;
private String typ;
public long getId() {
return this.id;
}
public void setId(long id) {
this.id = id;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
public String getTyp() {
return this.typ;
}
public void setTyp(String typ) {
this.typ = typ;
}
}
persistence.xml:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="GlassesPU" transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/glasses?zeroDateTimeBehavior=convertToNull"/>
<property name="javax.persistence.jdbc.password" value="mypwd"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.schema-generation.database.action" value="drop-and-create"/>
</properties>
</persistence-unit>
</persistence>
Error message:
Caused by: java.lang.IllegalArgumentException: Object: glasses.Hund#5d2e0422 is not a known entity type.
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.registerNewObjectForPersist(UnitOfWorkImpl.java:4228)
at org.eclipse.persistence.internal.jpa.EntityManagerImpl.persist(EntityManagerImpl.java:496)
at glasses.FXMLDocumentController.handleButtonAction(FXMLDocumentController.java:48)
... 54 more
Does anyone know the problem? Is there anything wrong in the Hund-class? Or in the persistence.xml?

Use your Hund class inside your persistence.xml like following example. Just place it between the properties and the persistence-unit tags.
</properties>
<class>glasses.Hund</class>
</persistence-unit>

If you don't want to list in the persistence.xml all your entities you can add the following line in the persistence.xml:
<exclude-unlisted-classes>false</exclude-unlisted-classes>

EntityManager doesn't save entity to MySQL database table

I use JPA MySQL to execute queries to database , but when I try to persists some entity no row is added to the table
Here is persistense.xml:
<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0">
<persistence-unit name="avtoparki" transaction-type="RESOURCE_LOCAL">
<description>
Persistence unit for the JPA tutorial of the Hibernate Getting Started Guide
</description>
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>Entities.City</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/world" />
<property name="javax.persistence.jdbc.user" value="root" />
<property name="javax.persistence.jdbc.password" value="tauren993" />
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
<property name="hibernate.show_sql" value="true" />
<!-- <property name="hibernate.hbm2ddl.auto" value="create" /> -->
</properties>
</persistence-unit>
</persistence>
here is entity class:
#Entity
public class City {
#Id
//#GeneratedValue(strategy=GenerationType.IDENTITY)
#Column(name="ID")
int id;
#Column(name="Name")
String name;
#Column(name="CountryCode")
String CountryCode;
#Column(name="District")
String District;
#Column(name="Population")
int Population;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCountryCode() {
return CountryCode;
}
public void setCountryCode(String countryCode) {
CountryCode = countryCode;
}
public String getDistrict() {
return District;
}
public void setDistrict(String district) {
District = district;
}
public int getPopulation() {
return Population;
}
public void setPopulation(int population) {
Population = population;
}
and here is code:
EntityManagerFactory emf = Persistence.createEntityManagerFactory("avtoparki");
EntityManager em = emf.createEntityManager();
City city = new City();
city.setCountryCode("Georgia");
city.setDistrict("AVOIE");
city.setName("Tbilisi");
city.setId(1);
em.persist(city);
em.close();
System.out.println("SAVED");
when I execute there is no error it just doesn't save it to table (the city table exists and the schema is the same

Seems to me, that you are missing a transaction. Try to save your city-object with following code:
private void save (City city, EntityManagerFactory emf) {
EntityManager em = emf.createEntityManager();
EntityTransaction tx = em.getTransaction();
try {
tx.begin();
em.persist( city );
tx.commit();
} catch( RuntimeException ex ) {
if( tx != null && tx.isActive() ) tx.rollback();
throw ex;
} finally {
em.close();
}
}

I would try an explicit flush em.persist(), em.flush(), em.close(). Just to verify.

You should create a Default no-args constructor
public City() { }
Hibernate uses reflection to create objects